CHEMICAL CHARACTERS OF THE WATERS OF ANGAT 



AND MONTALBAN RIVERS 



By R. H. Aguilar 



Of the Bureau of Science, Manila 



At the request of the Metropolitan Water District of Manila, 

 a systematic study of the quality of the waters of Angat 

 River and its most important tributaries was undertaken by 

 the Bureau of Science. This study, however, was limited to the 

 portion within the mountainous regions northeast of Bulacan 

 Province, comprising an area of about 732 square kilometers. 

 No surface water in the Philippine Islands has ever been so 

 systematically and thoroughly studied as has this river water, 

 not even excluding Montalban River, which is the present source 

 of the water supply for Manila. 



A survey of the river was made in May, 1921, by a party of 

 chemists of the division of general, inorganic, and physical 

 chemistry of the Bureau of Science for the purpose of taking 

 observations in situ and selecting convenient stations for collect- 

 ing water samples for analysis. 



Six stations were established along the course of the river, 

 within the territory under observation, and their exact locations 

 are shown in the accompanying sketch (Plate 1). The daily 

 collection of samples, at 6 a. m. and at 6 p. m., began May 21, 

 1921, and continued for one year. Composite samples made up 

 of seven days' collections from each station were forwarded to 

 the laboratory in Manila for analysis. 



In as much as no work of this nature had ever been done on 

 the water from the present source of the Manila water supply, 

 it was thought advisable to locate a seventh station, on Mon- 

 talban River, about 2 kilometers above the dam. The collection 

 of water samples from this station began July 28, 1921. 



The work of investigation is now far enough advanced (May, 

 1922) to justify the discussion of the chemical characteristics 

 of the waters, the relation of their various chemical constituents 

 with the general geology of the drainage areas, and their value 

 for industrial purposes. The notes on the survey and the re- 



